Posted
by
timothyon Saturday April 20, 2013 @07:08AM
from the but-you-must-haul-chuck-yeager-around dept.

derekmead writes "Having completed intense review of the aircraft's flight systems and functionality, component reliability, two weeks ago Boeing completed testing on the last item on its list, the plane's battery housing. The FAA on Friday approved the new system. That means the 787, which Boeing has continued to build while new battery solutions were developed, will now be able to resume regular flights as soon as workers are able to carry out an overhaul of the planes that need the upgrade. 'FAA approval clears the way for us and the airlines to begin the process of returning the 787 to flight with continued confidence in the safety and reliability of this game-changing new airplane,' Jim McNerney, CEO of Boeing, said in a news release announcing the approval."

This is actually a very good point. What the above poster is referring to is the ETOPS rating (which is the time from the nearest airport assuming that an engine fails). The 787 was designed to maximize its ETOPS rating, with an attempt to get it up to 330 minutes. Given its 14,000 to - 15,000 km range, a 330 minutes ETOPS would allow it to fly directly to almost any destination (including over the poles). Anything that reduces the ETOPS rating will make the aircraft more inefficient for long distance flights.

In any case, I'd assume that the fixed 787 will have at least a 180 minutes ETOPS rating which shouldn't cause too much pain (which is what it had before the battery problem occurred). If the FAA is being harsh, they may limit it to 120 minutes, which would particularly affect Pacific routes.

Let's have a dose of reality here. The root cause is PRESUMED to have been manufacturing defects. Nobody at Boeing or the FAA seems to have genuinely evaluated the likelihood that the lithium ion technology has BUILT-IN liability in the basic concept.

The only real question here is whether the protective redesign is adequate to contain the inevitable battery failures which will come, without setting the plane on fire or releasing poisonous fumes into the cabin.

Yuasa (the Japanese battery maker) blame the charging regime. They wanted the secondary regulator, Boeing disagrees.http://www.reuters.com/article/2013/02/28/us-boeing-787-report-idUSBRE91Q1CU20130228

Your laptop battery has a regulator in it, it's a smart battery, the chip tracks the coulombs in and out of the battery and adjusts the charge voltage as the battery ages. It also has a thermocouple on it to check the temperature during charging, to stop it overheating. If the battery has too many metal spikes

They seem to be fine with engine blade off events, engine fires and other engine related issues, so LNG as they are all properly contained - so no particular reason they wouldn't be fine with other components having the same restrictions.

Nobody at Boeing or the FAA seems to have genuinely evaluated the likelihood that the lithium ion technology has BUILT-IN liability in the basic concept.

Because that would take time to re-certify the entire electrical system. And it would put Boeing in a position of having to admit, "We were wrong." That, IMO, is the major issue. Once Boeing is wrong once, then all subsequent work they do could be second guessed.

The issue of fire containment isn't as difficult to demonstrate. We know the total energy stored in the battery. We assume it is converted to heat within some reasonably short time period. Someone whips out a slide rule and figures how much of tha

Expensive isn't the word for it. Changing the battery technology would require months of re-engineering work and months more of certification, possibly grounding the plane for a year, and that doesn't factor in the performance loss from the extra weight. The result could cripple Boeing, possibly fatally, to implement a solution that probably is not required.

They performed a great deal of testing on the new architecture including setting off a propane explosion. The containment system held and vented prop

The FAA is satisfied with the solution, and they're the ones who are going to get blamed if it fails catastrophically

Which counts for absolutely nothing. It's not as if individuals in the FAA will go to prison for negligence. There is no sanction for the FAA simply signing something off ( after all, they certified the original battery installation ).

In the backward Soviet Union, a new airliner type would be operated on domestic cargo and mail flights for 12 to 18 months before being assessed for carriage of fare-paying passengers. We didn't adopt that practice in the west because it was more important for the bottom li

Expensive isn't the word for it. Changing the battery technology would require months of re-engineering work and months more of certification, possibly grounding the plane for a year, and that doesn't factor in the performance loss from the extra weight. The result could cripple Boeing, possibly fatally, to implement a solution that probably is not required.

And most likely, not work at all.

The new airplanes use a lot of electricity (the generators on the 787 generate a total of 1.5MW of power - about 5 time

No. This battery (the GS Yuasa cells) don't suffer from these sorts of failures in other applications. They are not a new product, built only for Boeing. So, unless we are to believe that GS Yuasa has been producing the units shipped to Thales from a special, substandard manufacturing line, this is not the cause.

The fireproof battery box solution solves one of two problems: It prevents an 'eventful' battery failure from propagating to other aircraft systems and components. It does not demonstrate the battery system reliability that Boeing had initially assumed in their certification analysis. If the demonstrated reliability to date is not sufficient for ETOPS [wikipedia.org] operation, Boeing still has some homework to do. Failing to understand the nature of the faults means that Boeing cannot, with any certainty, claim to have reset the reliability numbers back to the original ones provided by certification analysis.

"Before the planes can fly, they must be fitted with a "containment and venting" system for both lithium-ion batteries on the 787, the FAA said. That includes a stainless-steel enclosure to prevent heat, fumes or fire from spreading if a battery overheats in flight. Batteries and battery chargers must also be replaced with different components, the FAA said"

I suspect replacing the batteries and chargers is the intended solution, with the enclosure and venting system being a 'just in case it happens again an